The present invention relates to a photo sensing integrated circuit device comprising a light receiving element for receiving incoming light, and a signal processing circuit (including transistors) for processing a detected light signal.
Furthermore, the present invention relates to a circuit adjustment for the photo sensing integrated circuit device.
In a detection of incoming light, a light signal is detected as a weak signal when the light is detected by a light receiving element, such as a photo diode. In general, such a weak signal needs to be processed by an appropriate signal processing device including as an amplifier and/or a digital converter. However, a circuit arrangement with additional and separate circuit elements is weak when subjected to extraneous noises and therefore tends to cause an erroneous detection.
To solve this problem, it may be possible to integrate the light receiving element and the signal processing circuit. When these members are integrated, it is necessary to guide the incoming light exclusively to the light receiving element. If the light enters into the signal processing circuit, unnecessary photoelectric current may be produced. This will result in an erroneous detection.